It's simple. The possibility of "sodomites" existing at some point, in some place, is flat out excluded from the get-go. This attitude is called gay erasure, and it is an actual agenda (oh the irony) promoted predominantly by right-wing people.

What is being denied here is the natural occurence of gay relationships.

The only reason that would make sense is if

A) they believe homosexuality is projected onto everything in an attempt to normalize it (re: "agenda"), implying the *need* to project